The present invention relates to an internal chuck for introduction inside two tubes, e.g. pipe sections, to be butt joined by welding of their adjacent ends.
It is already known, for example from the U.S. Pat. No. 4,053,973, to use an internal chuck to move two tubes closer to one another so as to bring together the ends which are to be welded.
U.S. Pat. No. 4,493,966 discloses an internal chuck with two longitudinally spaced zones, one of the zones being intended for butting the tubes and the other zone for welding them, the chuck being provided with means of longitudinal displacement over a length equal to the distance separating these two zones.
However, this last-mentioned type of internal chuck does not itself apply a force to move the two tubes towards one another.